There is enough aftermarket performance equipment being made today for the Buick Nailhead engine that you could assemble a fire-breather without ever visiting a swap meet or eBay, although there are still good vintage external items out there in fairly good numbers for the traditionalists. Since these engines have excellent performance to start with (stock with a good cam profile and 10:1 compression), about all street rodders are concerned with are the intake and exhaust. Sanderson Headers has the hot side covered, and the right year and model of original cast-iron manifolds can work quite well in some applications. What's hard to find is a left-side manifold that clears both the firewall and steering. New Tri-power intakes are available from Offenhauser (see Exeter Auto Supply) and Streamline Hot Rod Parts carries the new Eelco dual-quad and 6x2 intakes.
When shopping for a vintage intake, be aware that there are three widths of manifolds. Measuring from one of the front boltholes to the one on the opposite side, the 264/322 manifolds measure 8 1/4 inches, 364s measure 8 5/8 inches, and 401/425 intakes measure 9 inches.
Recent dyno tests on Eric Schmidt's well-built 425 Buick at Craig Shuck Motorsports showed results of 470 lb-ft of torque at 2,600 rpm, and 370 hp at 3,600 rpm, which is more than enough to make your rear tires dance around like water drops on a hot frying pan! Also interesting in his test results were that Tom Telesco's adjustable billet roller rockers (see Classic & Muscle Automotive) were worth some 13 hp, the Eelco 2x4 had the same power as a vintage Edelbrock 2x4, and that the Sanderson shortie headers were about the same power as cast-iron manifolds, but moved the powerband up a little.
When it comes to dressing for the party, Buicks look as good as anything out there, short of a blown Hemi with M/T valve covers. Offy still makes their finned valve covers, as do Mooneyes, Milr Products, and Eelco. O'Brien Truckers, Moon, and Milr Products all make finned aluminum valley covers. Ignitions are available ranging from new billet MSD distributors to Joe Hunt Magneto's "mag-alike" to vintage Mallory or rare W&H DuCoil distributors. If you want modern performance with the original look, send your stock distributor to Dave's Small-Body HEIs, where Dave Ray will rebuild your distributor and install modern electronics and adjustable vacuum advance while keeping the outside stock.
For a vintage engine suitable for today's hot rods, Buick Nailhead engines are still in decent supply. Though they're not as cheap as a small-block Chevy or as expensive as a 409 or Hemi, we've seen numerous complete Nailhead motors going for $500-$600. (This author bought a running '65 401 for $600 with a rebuilt TH400.) Watch your local classified papers and hit the swaps. It may be unwise to buy one from a source that is too far from you to permit a thorough examination before purchase, which is true for any vintage engine.
Once you get "Nailed," you'll understand why these have remained so popular in hot rodding circles. For what you'd spend for a crate motor, you'll have a piece of automotive history in your engine bay that'll be good for horsepower and conversation for many years to come.